The term `skew' refers to the direction of the longer tail if
you stand the stem-and-leaf upright, or draw a histogram.
Here is the histogram of the left-skewed stem plot above.

Histogram of left-skewed data

The long tail, of course, denotes outlying or
extreme observations.
The left-skewed histogram above
contains outlying small observations, while a right-skewed histogram
would have outlying large observations.
A left skew also indicates that the smallest quarter of observations will be more spread out.
See the boxplot below.